Route 6

Route 6 is a desert route that connects Brimber City and Mt. Igneus. Immediately after entering the route, a fork splits the path, with the right one leading to a dead end that has many dirt piles, and the left one leading to Mt. Igneus.

Durant Nests
There are many dirt piles on the route, and they are in fact Durant nests. Have a Pokemon use Dig on these piles, and wild Durant may come out and fight the player. TM Dig is not available at the point where player first explores this route, but Hippopotas on Route 5 can learn Dig by levelling up.